HP Surestore Disk Array FC60 HP SureStore E Disk Array FC60 Service Manual (A5 - Page 37

Product Description Controller Memory Modules Each controller module contains SIMM and DIMM memory modules. Two 16-Mbyte SIMMs (32 Mbytes total) store controller program and other data required for operation. The controller includes two DIMMs, which provide 256 Mbytes of cache. Cache memory serves as temporary data storage during read and write operations, improving I/O performance. When cache memory contains write data, the Fast Write Cache LED, on the front of the controller enclosure goes on. See Figure 13. Controller Fan Modules The controller fan module is a single removable unit containing dual cooling fans and temperature monitoring logic. See Figure 13. It includes five LEDs that indicate overall system status and controller fan status. The fans provide cooling by pulling air in through ventilation holes, moving it across the controller cards, and exhausting it out the ventilation holes in the fan assembly. The dual fans provide a redundant cooling system to both controller modules. If one fan fails, the other continues to operate and provide sufficient air circulation to prevent the controllers from overheating until the fan module is replaced. The fan module plugs into a slot on the front of the controller enclosure, and has a handle and captive screw for easy service. Array Controller Enclosure Components 37